Plane line dental articulators can provide for the mounting of dental casts with or without gypsum (plaster). The articulators can simulate the movements of the lower jaw relative to the upper jaw on the articulator, an action which does not normally match the functioning of these parts in the oral cavity. With existing apparatus of this type, adjustment is limited, especially to the height of the dental cast.
Earlier articulators for the purposes described have had disadvantages resulting from, for example, the sensitivity to dimensional changes in the plaster used in cast mounting but this can cause distortion of the articulation because of the fact that the articulator cannot be adjusted with relation to the height of the dental casts. The articulator is also difficult to handle since the user must hold the articulator frame together with the mounted casts during prosthodontic work
Removal of the casts from the articulator is carried out by breaking the plaster which can jeopardize the integrity of the cast and damage the articulator. Because the casts in many cases are mounted directly on a metal frame, the articulator generally is applicable only to a single use.
With articulators which do not mount the casts with plaster, the mounting of the cast is time-consuming because of the nature of the molding process used and the manner in which the cast must be manipulated.
In many instances with this second type of articulator, the cast mounting is not sufficiently firm and the accuracy of the prosthetic work is jeopardized. The versatility of the system is greatly limited.
These drawbacks were overcome by the apparatus described in application Ser. No. 08/050,070, in which a base is connected by a post to a head and both the base and the post were provided with bars having dovetail grooves in which dovetail formations of the member engaged in the cast could be received.
According to that system, to secure accurate movements on the articulator and the harmonization thereof with the normal movements of the lower jaw, the articulator provided a new system located on the lower element of the articulator which executes the movements while making available the upper element of the articulator for the same movements of the lower jaw.
A sleeve stopper and holder has a treble function by which the dental articulator can be applied to cases of cast mounting with or without gypsum (plaster).
My earlier articulator offered a solution to the problem of adjusting the articulator with relation to the height of the cast by providing a vertical guide meant for the vertical movement of the upper element of the articulator which can be adjusted depending on the height of the dental cast.
The mounting of the dental casts on the articulator by means of plaster was carried out on the disposable rubber sleeve-stopper and not directly on the metallic frame, thereby facilitating the removal and exact remounting of the casts thereon.
The use of the sleeve-stoppers prevented the plaster from dimensional change because the stoppers, which were rubber pins built into the sleeve-stoppers, come into direct contact with the casts which they support during their mounting on the articulator and limit to a minimum any dimensional change. The stoppers also functioned as guiding points determining the even or uniform plaster quantity used for the mounting of the casts on the upper and lower jaw.